Glassware press-molding machines for manufacturing for example, dinner plates, cups, tumblers, glassbrick halves and the like are quite well known. Conventionally these machines employ a two-part lower mold, the central portion of which is movable to elevate the pressed article above the surface of the outer portion of the mold to permit it to be grasped by some sort of handling means for transfer to a conveyor for heat treating, decorating, glazing or other operations. The usual mechanism for taking the pressed ware out of the molds employs radial tongs in which the two tong halves, 180.degree. apart, support the ware along sectors of approximately 30.degree. each. Such tongs must be accurately centered and properly operated to avoid injury of the ware and further, the ware must be cooled while in the mold to a point where it is completely self supporting as otherwise, it would sag once engaged by the tongs.
Due to highly concentrated and therefore uneven heat transfer at localized contacts between the tong lifts and the surface of the ware, the ware is prone to develop what is known in the art as "cold checks." These are small star-like surface cracks which can later function as a starting point for catastrophic failure of the entire article. Prior art attempts to reduce these cold checks include forming the tong jaws of hard asbestos or covering the jaws with a rope made of asbestos or glass wool. This produces improved results but fails to eliminate the problem completely.
Another approach to the problem has been the use of vacuum cups made of porous metal plates or screens. Some of these have been covered with an asbestos or glass fabric to reduce metal contact and consequently avoid cold checks. The problem here has been that the suction cups have to have a very precise contour which matches the ware as atmospheric pressure will deform the ware to the shape of the vacumm cup unless the ware is cool enough to be self supporting. Another problem with this approach is the localized cooling which results in areas of mismatch between the surface of the ware and the surface of the suction cup which concentrates a stream of cold atmospheric air at this location producing undesirable strains in the ware and tending also to produce catastrophic failure. From the foregoing, it will be apparent that the speed of operation of glass press-molding machines is necessarily limited by the time required to cool the ware and the molds until the ware is sufficiently self supporting to permit safe handling with the mechanical contact means now employed.